rsext4 0.4.0

A lightweight ext4 file system.
Documentation 
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//! JBD2 journal checksum helpers.

use crate::{
    crc32c::{crc32c_append, crc32c_init},
    endian::DiskFormat,
    jbd2::jbdstruct::{JBD2_CRC32C_CHKSUM, JournalSuperBllockS},
};

/// Computes the checksum stored in the JBD2 journal superblock.
pub fn jbd2_superblock_csum32(jsb: &JournalSuperBllockS) -> u32 {
    let mut bytes = [0u8; 1024];
    let mut jsb_for_csum = *jsb;
    jsb_for_csum.s_checksum = 0;
    jsb_for_csum.to_disk_bytes(&mut bytes);
    crc32c_append(crc32c_init(), &bytes)
}

/// Updates the stored JBD2 journal superblock checksum.
pub fn jbd2_update_superblock_checksum(jsb: &mut JournalSuperBllockS) {
    if jsb.s_checksum_type == JBD2_CRC32C_CHKSUM {
        jsb.s_checksum = jbd2_superblock_csum32(jsb);
    } else if jsb.s_checksum_type == 0 {
        jsb.s_checksum = 0;
    }
}